<!DOCTYPE html>
<html>
<head>
	<title></title>
	<meta charset="utf-8">
	<style type="text/css">
	body{
		width: 1000px;
		height:1000px;	
	}
	.head{
		width: 1000px;
		height: 100px;
		background-color: blue;
	}
	.main{
		width: 1000px;
		height: 800px;
		overflow: hidden;
	}
	.left{
		width: 300px;
		height: 800px;
		float: left;
		background: green;

	}
	.zhong{
		width: 300px;
		height: 800px;
		background: black;
		float: left;

	}

	.right{
		width: 400px;
		height: 800px;
		float: left;
		background: red;
	}
	.bottom{
		width: 1000px;
		height: 100px;
		background-color: yellow;
		
	}

	</style>
</head>
<body>
<div class="head"></div>
<div class="main">
	<div class="left"></div>
	<div class="zhong"></div>
	<div class="right"></div>
</div>
<div class="bottom"></div>
</body>
</html>